Emma Raducanu says she is feeling the benefits of a more rigorous fitness regime as the US Open champion prepares to continue her French Open campaign.

Raducanu battled from a set down to overcome Czech teenager Linda Noskova in her Roland Garros debut.

"I think that it is definitely improving," Raducanu said when asked about her fitness.

"One thing that I have been doing in the lead-up for this week and the whole of last week, I was doing a lot in the gym."

Greek fourth seed Maria Sakkari, three-time Grand Slam champion Angelique Kerber and former world number one Victoria Azarenka are also in action in the women's singles draw on Wednesday.

Britain's Cameron Norrie, 13-time winner Rafael Nadal, defending champion Novak Djokovic, third seed Alexander Zverev and Spanish sensation Carlos Alcaraz will attempt to reach the men's third round.

Raducanu, who has battled a series of niggling injuries since her US Open triumph in September, said she has also endeavoured to add "unpredictability" to her game, knowing that she has lost the element of surprise that helped fuel her memorable run at Flushing Meadows.

The British number one said: "I think definitely players kind of know more about me, and they would have seen me play more whereas last year, maybe if I was just a random qualifier, they wouldn't have put as much research or looking at me, how I would play.

"To counteract that I'm always looking to improve in all sorts of aspects. I think one was definitely physically, just to be able to last in the longer points, especially on the clay courts.

"Also just adding elements of unpredictability in whatever way that may be."

Sasnovich, 28, who is competing under a neutral flag, beat Raducanu in straight sets when they met at Indian Wells in October in what was the Briton's first match as Grand Slam champion.

Meanwhile, British men's number one Norrie says he is relishing the latest opportunity to showcase his burgeoning clay-court credentials in his second-round match against Australian qualifier Jason Kubler.

"I'm more just locked in on the level and locked in on my next opponent," said 26-year-old Norrie, who backed up his ATP title triumph in Lyon by beating French wildcard Manuel Guinard in Monday's opener.

"I feel like I'm a more experienced player and a better player than I was a couple of years ago. I feel the same, but just my game's improved and I've just got to keep backing it up every day."

Having opened his title defence with a routine victory over Japan's Yoshihito Nishioka, Djokovic will face Slovakia's Alex Molcan, who is coached by the Serb's former long-time coach Marian Vajda, in the third match on Court Suzanne Lenglen.

Spain's Nadal, targeting a record-extending 14th singles title, plays France's Corentin Moutet in the night session on Court Philippe Chatrier.